In this experiment, potassium carbonate combined with a quaternary ammonium salt to form a strong base. The strong base created an anion from an ester of malonic acid. The ion reacted with bromobutane which was also in the reaction solution to give the product.
The yield product was a butyl derivative of malonic ester that was isolated by adding water to the reaction solution, and extracting with ether. The ether was dried and evaporated to give the product. Procedures: 0. 039g of trlcaprylmethylammonlum chloride, 0. 358g of 1- bromobutane, 0. 41 eg ofdlethyl malnote, and 0. 414g of potassium carbonate were mixed In a 5mL long-necked, round-bottom flask. The apparatus was set up according to figure 42. 1 . The distillation column was attached to be used as an alr condenser in rder for the reaction solution to reflux.
The flask containing the reaction solution was heated. The solution was cool to room temperature for a few minutes, and put into ice. The solution was transferred toa drawn off. The aqueous layer was extracted with two portions of 1. 5mL of ether. The combined organic extracts were dried over anhydrous calcium chloride pellets. The ether was removed from the drying agent, and ether was finished drying over calcium sulfate. The dry ether solutions were placed in a “dry’, tared 5mL long- ecked, round-bottom flask.
The ether was removed by distallion or evaporation in the hood. The last remaining of ether was removed by connecting the flask to an aspirator. The product was weighted. The therotical and percentage yield was calculated. A TLC plate in 30% heaxanes and 40% DCM was conducted to compare the product with pure diethyl n-butlymalonate and starting materials diethyl malonate and bromobutane. Data: Reaction: Diethyl n-Butylmalonate Compound Tricaprymethylammonium chloride (ammonium salt) Diethyl malonate I-bromo- butane
Potassium carbonate water Ether Boiling point 199. 30C 101 . 60C Molecular Weight 404. 47 g/mol 137. 03vmol Amount needed 0. 040g o. 40g 0. 35g 0. 41* 2. 5rnL 1. 5rnL+ 1. 5rnL Amount used 0. 039g 0. 416g 0. 358g 0. 414g 3. ornL Molecular weight Actual yield Theoretical yield Percentage yield Crude product diethyl n- butylmalonate 216. 28vmol 13. 056g gof diethyl malonate x MW of diethyl malonate x Imol of product MW of diethyl n- butylmalonate 1 mol of diethyl malonate 0. 416g x 1 mol x Imol of product 160. 17g 1 mol of ammonium salt mol x 216. ” 0. 56g TLC plate x 100 % Theoretical yield Total distance (cm) Distance migrated (cm) Rf value Starting material: Diethyl malonate 4. 4 cm 3. 5 cm Product: crude diethyl n- butylmalonate breaks apart to 2 compounds I-bromobutane or the TIC, I don’t remember what the running solvent was but if it was more polar than the more polar compound would be the 3. 1 cm one and vice versa. We can’t be sure about which is which though. I asked him and he said its 0k if you put that you’re not confident Which dot is a certain compound